Unspecified kidney donation--a review of principles, practice and potential.

Unspecified kidney donation is an emerging resource to bridge the gap between supply and demand of kidneys for transplantation. However, uncertainty remains among both the transplantation community and lay public with regard to the intention, motivation, and legitimacy of such donors. Even within programs that use unspecified kidney donors, there is a lack of consensus regarding how to optimize the potential of the gifted kidney (and indirectly potentiate the altruistic benefit for the donor). Despite emerging guidance on how to work up unspecified donors, centers have adopted individualized unspecified donor pathways with regards to assessment, evaluation, and use. There are a variety of models for unspecified kidney donation, ranging from donation directly to deceased-donor waiting lists to benefit one recipient or chain transplantations occurring simultaneously (domino-paired donation) or nonsimultaneously (extended altruistic donor chains) to benefit many. After a brief exploration on the basis of altruism, this review will discuss the assessment, evaluation, and reported outcomes associated with unspecified kidney donation. It will also critique current utilization models and highlight some unresolved controversies. The aim is to highlight the principles, practice, and potential of unspecified kidney donation to bridge the current disparate international practice.